Strip material for use in making center spot crowns



y 1938. J. B. EISEN 2,118,595

STRIP MATERIAL FOR USE IN MAKING CENTER SPOT CROWNS Filed July 14, 1936 INVENTOR Patented May 24, 1938' STRIP MATERIAL FOR USE IN MAKING. CENTER SPOT CROWNS Jay Bernard Eisen, Yonkers, N. Y., assignor to Ferdinand Gutmann & Ca, Brooklyn, N. Y., a corporation of New York Application July 14, 1936, Serial No. 90,466

- 3 Claims.

sive coating is applied to the tin, aluminum or 5 other metal foil, or the paper for protecting the central portion of the cushion disc of 'a crown cap, and though plastic, is non-tacky under normal temperatures, so as to preclude the adhesion of one convolution of a roll of the material to the adjacent convolution.

Prior to my invention, there has been extensive- 1y used in the production of crown caps, strip material coated on one face thereof with a heat fusible adhesive, such as gutta-percha, various resinous compounds and a cellulose derivative adhesive. While the adhesive coating of such strips was dry, nevertheless since such coatings were heat fusible, high temperatures in the store room where rolls of the strip material were kept, would frequently cause one convolution of a roll to adhere to the under convolution thereof with sufficient tenacity to prevent the free drawing of the material from the roll during the application of the center spot to a crown seal. 'This not only interfered with a continued operation of the machine used for this purpose, but caused wastage of the strip material. Furthermore, when such material having the heat fusible coating wassubjected to high room temperatures, there was a tendency at times of the adhesive coating upon one convolution of a strip being transferred to the facing or spot material of the under convolution where such-adhesive would be exposed to the action of the contents of a bottle if this defect were not detected during inspection and the crown discarded.

To correct the above difllculties, it has been found necessary with some of the adhesives, to store the rollsin a refrigerating chamber until a rollwas mounted in the feed mechanism of a spot applying machine. Chillingof the adhesive, however, has the effect of imparting excessive hardness thereto, so that when cutting a center spot disc from the strip there is a-tendency of the adhesive, even though it is only .002 or .003 of an inch in thickness, to flake from the strip of facing material. This is undesirable,,since absence of adhesive adjacent the edge of the disc may interfere with a proper bonding of the spot to the cushion disc of the crown.

In the event of the extrusion of a heat fusible adhesive from between the center spot disc and the cushion disc, this adhesive, when cold, becomes brittle, and when tumbling thecrowns in the capping or in the filling and capping machine,

the extruded hard adhesive becomes granulated and may be delivered to within the bottle. If the extruded material is not thus granulated, the heat of pasteurization or sterilization, after the application of the crown to a bottle, will soften the 5 adhesive and cause the bonding of the neck of the bottle directly to the uncovered portion of the cushion disc. This interferes with a free removal of the crown or causes an unsightly appearance of the neck of a bottle from adhesive thereupon. 10

With the above conditions in mind, I have produced strip material in which the facing stratum presented towards the contents of a bottle when a-crown is placed thereon, is of metal foilor paper of the type usually used in the production of center spot crowns. Upon the other face of the strip material is an'adheslve coating which is non-fusible by heat and, while the major portion thereof is plastic at all times, is whatmay be termed a dry adhesive lacking in tackiness sum- 20 cient to cause one convolution of the material in a roll to adhere to the under convolution or to the material of the facing strip proper.

The coating of adhesive becomes activated only upon the absorption of water by some of the 25 ingredients of the coating, so that in the method of applying center spots to the cushion discs ofcrowns, the adhesive is inert at all times, excepting immediately prior to, or substantially simultaneously with, the depositing, under light pressure, of a'disc cut from the strip upon the cushion disc of a crown.

The subjection of the strip material to high room temperatures has no effect upon the adhesive, so far as making it tacky is concerned, but will have a tendency to eliminate any vehicle of the adhesive which has not been completely evaporated during the application of the adhesive to the facing material proper. Heat alone will not soften the "adhesive nor make it tacky. It will not become brittle under normal temperatures. I In the event of extrusion of theadhesive during the productionof the crown, or during the application of a crown to a bottle, this will not resultin the granulation of the exposed adhesive in the manner, nor the undesirable results of such. granulation above referred to. During pasteurization or sterilization of the contents of'the container, the heat will have no tendency to causeadhesion. of any extruded adhesive 'to the neck of a bottle, so that even if some adhesive should contact with the neck of the bottle, this will not interfere with the proper removal of the crown and will not cause the fouling of the neck of the container. There is no likelihood of chipping of the adhesive when cutting a disc from the strip.

The adhesive used is applied to the facing material in the form of a colloidal solution, and the vehicle in which the other ingredients are in suspension is driven ofi or evaporated, preferably while subjecting the strip to temperatures above those prevailing in the factory or store room during abnormally high summer temperatures.

The adhesive, as applied to the facing strip material, contains in solution or in emulsion, latex and one or more adhesives which, upon evaporation of the vehicle, become tacky and bond the adhesive to the facing strip material, the latex, which is not strongly adherent, serving as a carrier for the adhesive ingredients whichis plastic followin the evaporation of the vehicle.

In the finished strip, the adhesive coating therefor contains an inert plastic carrier and one or more inert adhesives which become tacky only after a restoration of the vehicle of the original solution thereto.

The adhesive agents used are casein alone, or casein and albumen, both of which are nontacky when subjected to heat while. dry, and the latter of which, after coagulation, is non-tacky when subjected to heat. The dry casein is not affected by heat in any way. Albumen is made tacky when subjected in the presence of moisture, to heat within a range of from F. upward, at which temperatures the albumen coagulates and takes a permanent set.

As stated above, the residue remaining upon the strip after the elimination of the vehicle is a non-tacky plastic having high flexibility and possessing absorptive properties which will admit of the restoration of a vehicle in a volume sufficient to cause or permit the activation of ingredients in the coating by subsequent evaporation of the vehicle, or by chemical reactions resulting from the application of heat.

The invention consists primarily in strip material for use in making center spot crowns embodying therein a strip of non-absorbent, gas impervious, inert material having throughout one side thereof a thin surface coating of a homogeneous admixture of latex from which the vehicle has been evaporated to form a non-tacky, flexible and absorbent body or carrier, and dry casein dispersed throughout and bonding said latex to said strip material, said latex and said casein being in a ratio of substantially three to one; and in such other novel characteristics as are hereinafter set forth and described, and more particularly pointed out in the claims hereto appended.

Referring to the drawing,

Fig. 1 is a view of a short section of strip embodying the invention, broken away upon different planes;

Fig. 2 is a longitudinal section thereof;

Fig. 3 is a view of a short section of material embodying a form of the invention using a paper facing strip; and V Fig. 4 is a longitudinal section of the material shown in Fig. 3.

Like numerals refer to like parts throughout the several views.

Strip material embodying the invention may include a strip of center spot or facing material which will vary in width, according to the size of the crown or other closure in connection with which the strip is to be used. This facing or spot material strip may be of aluminum foil, tin foil or varnished kraft or express paper, or any other material commonly used in the production -of center spot crowns.

Aluminum foil is extensively used in center spot crowns employed in bottling beer and other malt liquors. Tin foil is extensively used in the bottling of mineral waters. Varnished kraft or express paper is extensively used in bottling fruit juices, wines and socalled soft drinks. Any of these materials may be used for one face of a strip embodying the invention.

In the accompanying drawing, a strip of this material is indicated at iii in Figs. 1 and 2, and. lOa in Figs. 3 and 4. In the former instance, the material is a metal foil; in the latter instance, a treated paper.

Throughout one face of the material ID or iUa is a coating Ii, the exact composition of which will vary to adapt the strip to the particular method to be followed in applying center spots to the cushion discs of crowns.

This coating includes a homogeneous admixture of an inert plastic body or carrier and a dry soluble adhesive bonding said admixture to said strip material. The body or carrier is latex, no vulcanizing medium being used therewith, and the dry soluble adhesive is casein or casein and albumen. The proportion of latex to casein in the admixture is preferably three to one of the solid constituents of the coating. These constituents are placed in suspension or emulsion in a suitable vehicle, the viscosity of the solution or emulsion being determined by the method followed in coating the strip material therewith.

During this coating operation, it is essential that the vehicle be driven off by evaporation under normal temperatures or with the aid of a slightly elevated temperature, so that in the coated strip there is substantially nothing but the solid constituents of the solution or emulsion. The ratio above stated refers to these solid constituents.

It is possible that during the coating operation all of the vehicle is not removed, but enough of the vehicle is removed to avoid any tackiness in the casein or in the body or carrier.

Latex alone will not adhere readily to either metal foils or hard paper. It is slightly adherent, but the bond between it and such materials is so light as to permit a ready stripping of the coating from the strip material, or vice versa. Casein on the contrary will, in the presence of a liquid, become tacky and, as the vehicle is driven therefrom, will adhere firmly to the strip material. Casein alone is not suitable because when dried out it becomes brittle. In the pres ence of latex, however, the casein will bond firmly to the strip material, but the coating as a whole will remain plastic. The plasticity of the coating and the lack of inherent tackiness permits the coated strip material to be collected in roll form following the coating operation, and the practical elimination of the vehicle prior to the collection of the strip in roll form precludes all possibility of succeeding convolutions of the strip in the roll adhering one to the other. This is true even when the roll is subjected to elevated temperatures, since heat does not make the coating tacky or cause it to flow.

The thickness of the coating is approximately .002 of an inch.

While casein will form a strongly adherent bond to metal foils, it may be found desirable, when the metal foil is used, to coat one surface of this metal foil with a lacquer stratum l2 prior to the application of the coating II to the strip.

This practice is not essential, but it may be followed to simplify the coating operation, since with a roughened surface, greater uniformity in the bond between the coating and the metal foil may be secured. In actual practice, however, I have found that the lacquering of metal foil is not essential if proper care is exercised in applying the coating mixture to the strip material.

This last condition is shown in Fig. 3 of the drawing, wherein the strip material itself is a varnished paper. With paper, the casein constituents of the coating mixture will unite without difficulty and bond thereto with sufficient firmness for the purpose for which the strip is intended for use.

The use of latex in the coating mixture is for the purposenot only of providing a body or carrier for the adhesive, but to maintain the coating in a plastic condition which will prevent the hardening of the adhesive over long periods and even after a center'spot cut from the strip is applied to a cushion disc. Furthermore. the latex constituent of the mixture when moistened, becomes sufficiently tacky to ensure the formation of a light bond between the center spot disc and the cushion disc during the machine operation of applying said spot to said disc. The use of latex permits the center spot disc to be pos tioned upon the cushion disc with sufficient 2.0? curacy. while avoiding possibility of side slipping of the center spot when pressure is applied thereto, following the depositing of the spot upon the cushion disc.

Casein will readily absorb water or other solvent which may be applied to the coating of the strip material, or to the cushion disc, and the ab' sorption of such liquid will condition the casein constituent of the coating so that by a subsequent evaporation or driving off of this vehicle, the casein constituent will be made sufficiently tacky to form a firm bond with the cork of the cushion d sc. While the liquid may be applied to the coating before cutting the disc forming the center spot therefrom, this is done. in the application of the center spot to a cushion disc. immediately prior to the action of the dies, so that during the cutting operationythe coating II is not sufficiently tacky to cause the fouling of the dies and the difflculty resulting from such fouling.

Since the coating is plastic when the center spot discs are cut from the strip. there is no tendency toward the chipping or flaking of the material of the coating from the strip material, thus ensuring continuity in the coating upon the disc to the extreme edge thereof. This is highly desirable.

When the coating H is composed of latex and casein only, as the active ingredients, no heat is required when applying the center spot disc to the cushion disc. although as in all cementing operations, pressure is necessary to ensure the desired intimate contact of the adhesive stratum to the cushion disc.

Before the cutting of the center spot disc from the strip, the coating II is firmly bonded thereto. The application of liquid to the exposed face of the coating ll does not impair this bond. While this liquid will be absorbed by the casein constituent of the coating, the quantity or volume of the liquid is not sufficiently great to impair the adhesiveness of that portion of the casein contacting with the strip material, notwithstand: ing the thinness of the coating.

Strip material having a coating consisting of casein and latex may be used in applying center spots to crowns without applying any moisture to the coating ll, provided that the cushion disc of the crown is coated with a similar plastic material throughout an area substantially co-extensive with the area of the center spot disc.

In a strip embodying the invention, the coating II is, firmly bonded to the material It or Illa by the casein constituent, so that in the subsequent procedure of applying center spot discs cut from this strip to the cushion disc of a crown, the only bonding action to be secured is between the coating II and the cushion disc.

While the latex in the admixture will cohere lightly to the facing material, the casein dispersed throughout this body or carrier presents a multitude of anchorage points preventing the separation of the strip material from the coating material as a whole. If it be desired to provide a stronger bond between the center spot disc and the cushion disc of a crown, I may include egg or blood albumen in the admixture of the coating ll, preferably the former. During the procedure of applying the center spot disc to the cushion disc, heat and pressure at a temperature which, within the time limit afforded by center spot applying machines, is used to bring the coating to a temperature of from 140 F. upward, within which range the albumen constituent will be coagulated so as to form a permanent bond by an adhesive which in part is water insoluble.

When albumen is included in the homogeneous admixture forming the coating ll, said coating is made up of substantially 27 parts of latex, 9 parts of casein and albumen within a range of from 8 to 16 parts. I have found in practice that while albumen in excess of 16 parts may be used,

it does not increase the effectiveness of the bond secured by means of this coating.

The latex used is pure latex, that is, no vulcanizing agents of any kind are admixed therewith or applied thereto. In making the strip, a solution or emulsion of latex and casein is first formed, the volume of the vehicle used being determined by the coating methods employed. The solution or emulsion must contain enough vehicle so as to be non-tacky to a degree which will facilitate its transfer by means of a roller to the strip of facing material, and yet must be sufficiently viscous to permit its application to said material and the evaporation of the vehicle within a short time interval before the strip is collected in a roll.

As stated heretofore, when the vehicle is removed by evaporation from the solution or emulsion applied to the facing material, the coating is substantially dry and will not adhere to the facing. material while in the roll. While heat may be used to hasten evaporation of, the vehicle, in the finished product the coating does not soften nor react in any way to heat at elevated factory temperatures.

When albumen is included in the admixture, it is placed insolution or emulsion by itself, and

' this solution or emulsion is admixed with a solution or emulsion of the casein and latex. When albumen is used, care must be taken while applying the coating to the strip material to avoid temperatures which will cause coagulation of the operation, the effect of which is to reduce the latex constituent of the mixture to a plastic form and the casein, and the albumen when used, to a dry state.

During the driving out of the vehicle, there is a stage during which the casein constituent becomes tacky so as to form a strong bond between the coating and the facing material, and since the casein is thoroughly dispersed throughout the body or carrier, the bond secured by the casein prevents the stripping of the coating material from the facing material, which can readily be done when latex alone is used. Because of the strong bond between the coating material and the facing material when applying a center spot to the cushion disc of a crown, the only bonding action required is between the coating and the cushion disc. Hence there can be no side slipping of the disc of facing material in relation to the coating, and since the tackiness resulting from the absorption of liquid by the casein or by the adherence of the plastic constituent oi the coating to a plastic coating upon the cushion disc will prevent side slipping of. the coating in relationto the cushion disc, the percentage of spots which will be off center to any appreciable extent is reduced to a minimum.

If, by reason of the application of liquid to the coating H the bond between the coating II and the facing material l0 should be weakened as a result of the penetration of this liquid through the coating, the effect upon the casein will merely be to again make it tacky, and side slipping will not occur from this condition. During the subbility of any substantial weakening of this bond due to the absorption of moisture from the air or from any other cause, in the event of a long delay between the production of the crowns and their use.

The coating ll isnon-fusible in the sense that when subjected to heat, even when albumen is included therein, it will not become soft or tacky.

As heretofore stated, it is more difllcult to apply the adhesive to a strip of metal foil than to a treated paper strip. This applies particularly to tin foil. By coating the strip with a thin film of a lacquer, greater uniformity in the continuity and thickness of the coating II is assured, although with the exercise of a proper degree of care, and the use of heat during the coating operation, lacquer may be dispensed with.

It is not my intention to limit the invention to a strip material in which the exact proportions of latex and casein, or of latex, casein and albumen herein given are used. I have found, however, in practice, that these proportions give highly satisfactory results.

Having described the invention, what I claim as new and desire to have protected by Letters Patent, is:--

1. Strip material for use in making center spot crowns embodying therein a strip of non-absorbent, gas impervious, inert material having throughout one side thereof a thin surface coating of a homogeneous admixture of latex from which the vehicle has been evaporated to form a non-tacky, flexible and absorbent body or carrier, and dry casein dispersed throughout and bonding said latex to said strip material, said latex and said casein being in a ratio of substantially three to one.

2. Strip material for use in making center spot crowns embodying therein a strip of non-absorbent, gas impervious, inert material having throughout one side thereof a thin surface coating of a homogeneous admixture of latex from which the vehicle has been evaporated to form a non-tacky, flexible and absorbent body or carrier, dry casein dispersed throughout and bonding said latex to said strip material, and albumen from which the vehicle has been evaporated.

3. Strip material for use in making center spot crowns embodying therein a strip of non-absorbent, gas impervious, inert material having throughout one side thereof a thin surface coating of a'homogeneous admixture of latex from which the vehicle has been evaporated to form a non-tacky, flexible and absorbent body or carrier, dry casein dispersed throughout and bonding said latex to said strip material, and albumen from which the vehicle has been evaporated, said admixture containing substantially twenty-seven parts of latex, nine parts of casein and albumen within a range of from eight to sixteen parts.

' JAY BERNARD EISEN. 

